If it's 1.6.4, download 1.6.4 to 1.6.5 patch, unzip on your computer and upload on the server (overwrite all files).

Make sure you are running Joomla 1.6.5 (check the footer of your Joomla administration panel). Now follow these simple instructions to update from Joomla 1.6.5 to Joomla 1.7.0.

To save your time, we will soon upgrade all out HotStart installations so you'll have Joomla 1.7 running out-of-the-box. You will be able to download templates/extensions for Joomla 1.5, 1.6 and 1.7 without additional charges.